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参数资料
| 型号： | SP7650EB |
| 厂商： | Exar Corporation |
| 文件页数： | 9/16页 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD FOR SP7650 |
| 标准包装： | 1 |
| 系列： | * |
APPLICATIONS INFORMATION
The capacitor type suitable for the output capac-
itors can also be used for the input capacitors.
However, exercise additional caution when tanta-
lum capacitors are used. Tantalum capacitors are
known for catastrophic failure when exposed to
surge current, and input capacitors are prone to
such surge current when power supplies are con-
nected “live” to low impedance power sources.
Although tantalum capacitors have been success-
The first step of compensation design is to pick
the loop crossover frequency. High crossover
frequency is desirable for fast transient response,
but often jeopardizes the power supply stability.
Crossover frequency should be higher than the
ESR zero but less than 1/5 of the switching
frequency or 60kHz. The ESR zero is contrib-
uted by the ESR associated with the output
capacitors and can be determined by:
fully employed at the input, it is generally not
recommended.
? Z(ESR) =
1
2 C OUT R ESR
The next step is to calculate the complex conju-
? P(LC) =
LoopCompensationDesign
The open loop gain of the whole system can be
divided into the gain of the error amplifier,
PWM modulator, buck converter output stage,
and feedback resistor divider. In order to cross
over at the desired frequency cut-off (FCO), the
gain of the error amplifier has to compensate for
the attenuation caused by the rest of the loop at
this frequency. The goal of loop compensation
is to manipulate loop frequency response such
that its crossover gain at 0db results in a slope of
-20db/dec.
gate poles contributed by the LC output filter,
1
2 L C OUT
When the output capacitors are of a Ceramic
Type, the SP7650 Evaluation Board requires a
Type III compensation circuit to give a phase
boost of 180 ° in order to counteract the effects of
an underdamped resonance of the output filter at
the double pole frequency.
Type III Voltage Loop
Compensation
G AMP (s) Gain Block
PWM Stage
G PWM Gain
Block
Output Stage
G OUT (s) Gain
Block
V REF
(Volts)
+
_
(SRz2Cz2+1)(SR1Cz3+1)
SR1Cz2(SRz3Cz3+1)(SRz2Cp1+1)
V IN
V RAMP_PP
(SR ESR C OUT + 1)
[S^2LC OUT +S(R ESR +R DC ) C OUT +1]
V OUT
(Volts)
Notes: R ESR = Output Capacitor Equivalent Series Resistance.
R DC = Output Inductor DC Resistance.
V RAMP_PP = SP6132 Internal RAMP Amplitude Peak to Peak Voltage.
Condition: Cz2 >> Cp1 & R1 >> Rz3
Output Load Resistance >> R ESR & R DC
Voltage Feedback
G FBK Gain Block
V FBK
(Volts)
R 2
(R 1 + R 2 )
or
V REF
V OUT
SP7650 Voltage Mode Control Loop with Loop Dynamic
Definitions:
R ESR = Output Capacitor Equivalent Series Resistance
R DC = Output Inductor DC Resistance
R RAMP_PP = SP7650 internal RAMP Amplitude Peak to Peak Voltage
Conditions:
C Z 2 >> Cp1 and R1 >> Rz3
Output Load Resistance >> R ESR and R DC
Date: 2/16/06
SP7650 Wide Input Voltage Range 3A, 300kHz, Buck Regulator
? Copyright 2006 Sipex Corporation
Date: / 5/06
SP7650 Wide Input Voltage Range 3A, 300kHz, Buck Regulator
9
? Copyright 2006 Sipex Corporation
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP7650ER | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| SP7650ER/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range 3A, 300kHz, Buck Regulator |
| SP7650ER-L | 功能描述:直流/直流开关调节器 Buck Regulator RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| SP7650ER-L/TR | 功能描述:直流/直流开关调节器 WIDE INPUT VOLTAGE RANGE, 3A 300k RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| SP7651 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Evaluation Board Manual |
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